xmax_automatic_plant_watering_system.ino

#include <SPI.h>
#include <SD.h>

const int chipSelect = 4;
const int waterPumpRelayPin = 8;
const int moisture_minimum = 400;
const int watering_delay = 1000;
const int loop_delay_minutes = 5;
const int loop_delay = 60 * 1000 * loop_delay_minutes;

int loopCount = 0;

void setup_serial();
void setup_sd();
void log_line( String text );

void setup() {
  setup_serial();
  setup_sd();  
  pinMode(waterPumpRelayPin, OUTPUT);

  log_line( "Moisture minimum: " + String( moisture_minimum ) );
}

void setup_serial() {
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
  Serial.println("Serial connected.");
}

void setup_sd() {
  Serial.println("Initializing SD card...");

  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
    Serial.println("End of program." );
    while( 1 ) { ; };
  }
  Serial.println("card initialized.");
}

void loop() {
  log_line("Loop #" + String( loopCount ) );
  loopCount ++;

  int moisture_reading = analogRead( 0 );
  log_line( "Moisture sensor: " + String( moisture_reading ) );

  if( moisture_reading > moisture_minimum ) {
    log_line( "Watering time: " + String( watering_delay ) );
    digitalWrite(waterPumpRelayPin, HIGH);
    delay(1000);
    digitalWrite(waterPumpRelayPin, LOW);
  }

  log_line( "Loop delay: " + String( loop_delay ) );
  delay( loop_delay );
}

void log_line( String text ) {
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  File dataFile = SD.open("datalog.txt", FILE_WRITE);

  // if the file is available, write to it:
  if (dataFile) {
    dataFile.println(text);
    dataFile.close();
    // print to the serial port too:
    Serial.println("Logging: " + text);
  }
  // if the file isn't open, pop up an error:
  else {
    Serial.println("Error opening datalog.txt");
    Serial.println("End of program." );
    while( 1 ) { ; };
  }
}